113 lines
2.6 KiB
Mathematica
113 lines
2.6 KiB
Mathematica
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function [ alphas, betas, triX, mask, xmin, ymin, npix ] = InitialisePieceWiseAffine( triangulation, sourcePoints )
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%INITIALISEPIECEWICEAFFINE Summary of this function goes here
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% Detailed explanation goes here
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triangulation = triangulation + 1;
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numPoints = size(sourcePoints, 1);
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numTris = size(triangulation, 1);
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alphas = zeros(size(triangulation, 1), 3);
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betas = zeros(size(triangulation, 1), 3);
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xs = sourcePoints(:,1);
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ys = sourcePoints(:,2);
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for i = 1:numTris
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j = triangulation(i, 1);
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k = triangulation(i, 2);
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l = triangulation(i, 3);
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c1 = ys(l) - ys(j);
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c2 = xs(l) - xs(j);
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c4 = ys(k) - ys(j);
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c3 = xs(k) - xs(j);
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c5 = c3*c1 - c2*c4;
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alphas(i, 1) = (ys(j) * c2 - xs(j) * c1) / c5;
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alphas(i, 2) = c1/c5;
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alphas(i, 3) = -c2/c5;
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betas(i, 1) = (xs(j) * c4 - ys(j) * c3)/c5;
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betas(i, 2) = -c4/c5;
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betas(i, 3) = c3/c5;
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end
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xmin = min(xs);
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ymin = min(ys);
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xmax = max(xs);
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ymax = max(ys);
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w = int32(xmax - xmin + 1);
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h = int32(ymax - ymin + 1);
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mask = zeros(h, w);
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triX = zeros(h, w);
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shape = [xs, ys];
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for i = 1:h
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for j = 1:w
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currTri = findTriangle(double([double(j)-1+xmin, double(i)-1+ymin])', triangulation, shape);
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if(currTri ~= -1)
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triX(i, j) = currTri - 1;
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mask(i, j) = 1;
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else
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triX(i, j) = -1;
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end
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end
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end
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npix = sum(sum(mask));
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end
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function [tri] = findTriangle(point, tris, controlPoints)
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numTris = size(tris, 1);
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tri = -1;
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for i=1:numTris
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if(PointInTriangle(point, controlPoints(tris(i,1),:)', controlPoints(tris(i,2),:)', controlPoints(tris(i,3),:)'))
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tri = i;
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break;
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end
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end
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end
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function inTriangle = PointInTriangle(point, v1, v2, v3)
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inTriangle = SameSide(point, v1,v2,v3) && SameSide(point, v2,v1,v3) && SameSide(point, v3,v1,v2);
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end
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function sameSide = SameSide(toTest,v1,v2,v3)
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x0 = toTest(1);
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y0 = toTest(2);
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x1 = v1(1);
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x2 = v2(1);
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x3 = v3(1);
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y1 = v1(2);
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y2 = v2(2);
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y3 = v3(2);
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x = (x3-x2)*(y0-y2) - (x0-x2)*(y3-y2);
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y = (x3-x2)*(y1-y2) - (x1-x2)*(y3-y2);
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if(x*y >= 0)
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sameSide = 1;
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else
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sameSide = 0;
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end
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% cross1 = cross( v3 - v2, toTest - v2);
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% cross2 = cross( v3 - v2, v1 - v2);
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%
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% sameSide = (cross1 * cross2') >= 0;
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end
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